According to the YES Network announcers, David Robertson is headed to the DL with a groin injury. No word yet on the extent of it, but it's odd to hear about this considering he was throwing 94-95 mph yesterday afternoon. Shawn Kelley will take over the closing duty, and he notched his first save today. The Yankees will probably call up another reliever, and my bet is Preston Claiborne. Long term, the Yankees already had little depth with high leverage relievers, and although they could get something big out of Dellin Betances or Adam Warren, the team may want to target another reliever in an Eduardo Nunez trade.
Update: (4:32 PM) In unrelated news, the Yankees announced that Mark Teixeira's injury was a grade 1 hamstring strain. This is the most minor strain, so Teixeira may only need the minimum 15 days on the DL.

Update: (4:37 PM) Robertson's injury is also a grade 1 strain, but to the groin. So this could also be a short DL trip.